Tensiometer



Jan. 2s, 1944. P, LESVSMNN 2,340,067

TENSOMETER Fi'led NOV. 28, 1940 2 Sheets-Sheet 2 l l l D 5gg j, L r' wlTNEssEs; 4 y mvx-:NToR

y Gerhard .PL ess/77mm.

Patented Jan. 25, 1944 UNITED STATES PATENT OFFICE TENsIoMETER Pennsylvania Application November 28, 1940, Serial No. 367,499

c claims.

My invention relates, generally, to tensiometers, and more particularly, to tensioning de- Y vices and indicating means for subjecting a strip of material 'to tension and indicating the degree of strip tension as the strip passes between adjacent work devices.

In the operation of steel strip rolling mills, it is common practice to subject the strip to 'tension as it extends between adjacent roll stands, and/or between a roll stand and an adjacent reel, by causing a tensioning roller to bear against the strip to apply a transverse deflecting force to the strip.

Such tensioning rollers are usually arranged to be actuated by a single operating device which rigidly connects the two end bearings of the tensioning roller and thereby imparts the same movement to both ends of the tensioning roller. Such a tensioning device is shown and described in my copending application Serial No. 252,934, iiled January 26, 1939,v now Patent No. 2,250,540, issued July 29, 1941, and assigned to the assignee of the present application.

Differences in the screwdown settings of the two ends of the reducing rolls results in a difference of strip reduction from one side of the strip to the other, and even though the desired total tension may be applied to the strip, all or most of the tension may be applied to one side or edge portion of the strip, and there may be such an unbalance of the strip tension as to tear the strip atl the point where the excess tension is applied.

An object of my invention is to provide a tensiometer for a strip rolling mill having a single actuator which shall function to indicate the degree of tension on the two sides of the strip, the total tension on the strip, and the tension differential between the two sides of the strip, which shall be simple and eflicient in operation, and inexpensive `to manufacture, install and maintain.

These and other objects and advantages ofthe invention will vbe apparent from the following detailed description taken in connection with the accompanying drawings, in which like parts are designated by identical or similar reference characters, and in which:

Figure 1 is a perspective View of a strip tensioning device embodying the principal features of one embodiment of my invention;

Figs. 2 and 3 are perspective views, partly in section, of two other embodiments of the invention; and

Fig. 4 is a-wiring diagram of the indicating `system by which the strip tension values are indicated to the mill operator.

In practicing the invention in the embodiment of Fig. 1, a tensioning roller I0 is rotatably mounted upon supporting arms I2 and I4 which are mounted upon a shaft I6 for rotation with the shaft. The shaft I6 is actuated by a suitable power translating device, such as a pressure fluid operated piston and cylinder I3,l to cause the tension-roller to bear against a strip of material I9 as it passes between adjacent strip roll stands or between a roll stand and an adjacent strip reel. The strains of the shaft I 6 between the actuating device I8 and the supporting arm I4 and between the supporting arms I2 and I4, actuate strain gauge means 2li and 22 respec-l tively.

In the embodiment of Fig. 2, the supporting arms I 2 and I4 are fixed to a sleeve member 24 adjacent the ends thereof and the sleeve member is secured to the shaft I 6 for rotation therewith at a point intermediate the ends of the sleeve. The strain gauges 20 and 22 in this embodiment of the invention respond to the strain of the parts of the sleeve 24 between the point at which the sleeve is secured to the shaft I E and the respective ends of thesleeve.

In the embodiment of Fig. 3, the supporting arm i2 is fixed to the shaft' I6 and the supporting varm I4 is fixed to a sleeve member 26 which is also actuated by the power translating device I8. l

The strain gauge means 2i) andA 22 may be connected in an electrical circuit as shown in Fig. 4, to actuate suitable indicating, recording, or control devices 28 and 30.

Considering the invention more in detail, the tension roller I0 in Fig. 1 has its ends rotatably mounted in suitable bearings in the supporting arms I2 and I4. VThe shaft I6 to which the supporting arms I2 and I4 are secured is rotatably mounted inV suitable bearing members on the brackets 32, 34 and 36, which in turn, are mounted 0n a beam member 38 which is secured by any suitable means to the mill-housing members 40 and 42 of a strip rolling mill with which the tension device is associated. The shaft I5 is connected to be rotated by the power translating device I8 by means of a crank arm 44.

The strain gauge means 2Q comprises strain gauges it and 48 mounted diametrically opposite each other on collar members 5E! and s2 which are secured in spaced relation on the shaft I t; TheV strain gauge means 22 comprises strain gauges 4S and Q8 similarly mounted on the shaft I6.

The strain gauges 46 and 48 may be any suitable devices responsive to small displacements. The wiring diagram of Fig. 4 comprises electrical bridge circuits, one of which includes the strain gauges 46 and 48 and the indicating device 28, and the other of which includes the strain gauges 46' and 48 and the indicating device 3c.

The coils 5S and 58 of the strain gauge 46 are connected in series circuit to a source of alter'- nating current power as indicated. An impedance coil 60 is also connected to the source of alternating-current power and a midpoint of the coil 60 is connected through the indicating device 23 'K to the connection between the coils 5B and 5B. Thus the coils 5f: and 58, the impedance coil 6I) and the indicating device 2t are connected in a bridge circuit which may be unbalanced by the movement of the armature member' 62 with respect to the coils 55 and 58 and the unbalance of which will actuate the indicating device 23. Similar bridge circuits are provided for the strain gauges 48, 45' and 4S" as indicated. The strain gauge means including the two strain gauges 4t and 48 is provided to prevent false indications due to bending of the shaft I6 under the stress of the torque transmitted to the tensioning roller I0.

The angular position of the tensioning roller supporting arms I2 and I4 with' respect to the normal pass line ofthe strip may be such as to provide any desired tension-deflection characteristic of the tensioning device, as explained in my hereinbefore referred-to Patent No. 2,250,540, and the indicating means 28 and 39 may be so calibrated asto indicate the tension on the strip as measured by the strain to which the strain gauge means 2t? and 22 are responsive.

The indicating instrument 28 will thus indicate the total tension on the strip since the strain of the part of the shaft I6 between the operating arm 44 and the supporting arm Ity is a measure of the total torque applied to the tensioning roller. Similarly, the tension device 22 responds to the torque applied to the end of the tensioning roller Ii! which is supported by the supporting arm vI? and the indicating instrument 39 which is responsive to the strain gauge means 22 will indicate the tension applied to that edge portion of the strip which is acted upon by the end of the tension roller It which is supported by the supporting arm i2. Thus the indicating instrument 28 will show the to-tal tension on the strip, the indicating instrument 3D will show the tension on one edge portion .of the strip, and if the indication given by the instrument 30 is more or less than one-half the indication given by the instrument 28, it will be apparent that there is a tension differential between the two edge portions of the strip and the mill operator may accordingly so adjust the screwdown of the mill rolls as to balance the tension on the two edge portions of the strip.

In the embodiment of the invention of Fig. 2, the sleeve member 24 may be secured to the shaft I6 for rotation thereby by any suitable means such as a key member 54 at a point intermediate its ends. In this embodiment of the invention the supporting arms I 2 and I4 are secured in any suitable manner to the sleeve 24 adjacent the ends thereof. The shaft I6 is rotatably mounted in the brackets 32, 34 and 36 as hereinbefore explained and operating torque is transmitted to the tensioning roller, through the shaft I6, the sleeve 24, and the supporting arms l2 and I4.

In the operation'of this embodiment of the invention the strain gauge means and 22 are disposed between the point at which the sleeve 24 is secured to the shaft I6 and the supporting arms I2 and I4, and thus respond to the strain of these respective portions of the sleeve 24. In this embodiment of the invention, the indicating devices 28 and 30 may be similarly calibrated Vand will indicate the tensions on the respective edge portions of the strip and any unbalance or differential between the tensions on the two edge y portions of the strip may be observed and the mill screwdown setting or any other necessary adjustment may be made accordingly.

In the embodiment of the invention of Fig. 3,

` it will be apparent that the torque tranmitted Y of the tensioning roll supported by the supporting fic arm E4 will be transmitted through the sleeve 26.

` The strain gauge means 20 and 22 are disposed to be responsive to the strains of the sleeve 26 and the shaft I6, respectively, and in the operation of the device the indicators 28 and 30 will give indications of the tensions on the respective edge portions of the strip. It is to be understood that the indicating instruments 28 and 30 and the strain gauge means 2!) and 22 may be any suitable instruments for performing the functions herein described and that any other suitable circuit arrangement that will function accurately may be employed for connecting these elements of the system.

. It will be seen that I have provided a tensioning device which shall function to subject a strip of material to tension as the strip extends between adjacent Work devices, and which shall function to indicate the tensions on the two edge portions of the strip, so that any differential of strip tension between the two edge portions of the strip may be observed and the proper adjustments made to provide uniform tension throughout the width of the strip.

In compliance with the requirements of the patent statutes, I have shown and described herein the preferred embodiments of my invention. It is to be understood, however, that the invention is not limited to the precise construction shown and described but is capable of modification by one skilled in the art, the embodiments herein shown and described being merely illustrative of the principles of my invention.

I claim as my invention:

l. In a strip tensioning device. a tensioning roller disposed to bear against a strip or" material as it extends between adjacent work devices to thereby subject the strip to tension by deflectit from the line between. the worl: devices,l a supporting arm for each end of tensioning roller, means rotatably mounting each end of said roller on its Supporting arm, shaft means rotatably mounted substantially parallel to and displaced radially from the tensioning roller for supporting and actuating the supporting arms, actuating means disposed to impart a rotational torque to said shaft means to thereby cause said tensioning roller to bear against the strip and apply a transverse deflecting force thereto, separate electromagnetic strain gauge means mounted upon said shaft means responsive to the strains of separate predetermined portions of the said shaft means which are stressed differently by the separate torques applied through the shaft means to the separate tensioning roller supporting arms, energizing circuits for each of said separate electromagnetic strain gauge means, and electroresponsive indicating devices connected in said circuits to be controlled by said strain gauge means in accordance with the torques in said separate predetermined portions of the shaft means.

2. In a strip tensioning device, a tensioning roller disposed to bear against the strip and apply a transverse force thereto to thereby subject the strip to tension, a supporting arm for each end of said roller, means rotatably mounting each end of the tensioning roller on its supporting arm, shaft means rotatably mounted substantially parallel to and displaced radially from the tensioning roller, means mounting said supporting arms upon and for rotation by said shaft means, means adjacent one end of said shaft means for applying a torque to the shaft means to thereby cause said tensioning roller to bear against the strip and apply a transverse deiiecting force thereto, rst electroresponsive strain gauge means mounted upon said shaft means to be responsive to the strain of a predetermined portion of said shaft means between the point at which the torque is applied and the adjacent support arm, and second electroresponsive strain gauge means mounted upon said shaft means between the supporting arms to be responsive to the strain of a predetermined portion of said shaft means between the supporting arms, and an electroresponsive indicating device controlled by each of said strain gauge means for indicating strip tensions as determined by the torques applied to said separate predetermined portions of the shaft means.

3. In a strip tensioning device, a tensioning roller disposed to bear against a length of strip material as it extends between adjacent work devices and apply a transverse force thereto to thereby subject the strip to tension, rotatably mounted shaft means, a supporting arm for each end of said roller mounted in spaced relation on said shaft means, means rotatably mounting each end of the tensioning roller on its supporting arm, a force applying means operatively connected to said shaft means to effect rotation thereof to cause said tensioning roller to apply a transverse deflecting force to the strip, and means including separate gauge means mounted on separate predetermined portions of the shaft means responsive to the strain of said separate predetermined portions of the shaft means for indicating the tensions applied to diierent portions of the strip in accordance with the torques applied to the said separate predetermined portions of the shaft means.

4. In a strip tensioning device, a tensioning roller disposed to bear against a length of strip material as it extends between adjacent work devices and apply a transverse defiecting force thereto to thereby subject the strip to tension, a supporting arm for each end of said roller, said roller being rotatably mounted thereon, shaft means rotatably mounted substantially parallel to and displaced radially from the tensioning roller, said supporting arms being mounted upon and for rotation by said shaft means, pressure fluid actuated means operatively connected to one end of said shaft means for applying a torque to the shaft means to thereby cause said tensioning roller to bear against the strip, rst strain gauge means mounted directly upon said shaft means between the point at which the torque is applied thereto and the adjacent supporting arm to be responsive to the strain in this portion of the shaft means, second strain gauge means mounted upon said shaft means between the supporting arms to be responsive to the strain of this portion of said shaft means, and separate indicating means responsive to the respective first and second strain gauge means for indicating, respectively, the total tension on the strip and the tension on the edge of the strip most remote from the end of the shaft means to which torque is applied caused by the force exerted on the strip through the portion of the shaft means extending between said supporting arms whereby a differential in tension on the two edges of the strip may be determined by a comparison of the indication of the second indicating means with one-half of the value of the indication of the rst indicating means.

5. In a strip tensioning device, a tensioning roller disposed to bear against a length of strip material extending between adjacent work devices and apply a transverse force thereto to thereby subject the strip to tension, a supporting arm for each end of the roller, means mounting each end of the roller for rotation on its supporting arm, a rotatably mounted shaft substantially parallel to and radially spaced from said roller, a sleeve member concentric with and overlying a portion of said shaft, means securing said sleeve member to and for rotation by said shaft at a point intermediate the ends of said sleeve member, means securing said supporting arms to the opposite ends of said sleeve member, means for applying a torque to said shaft to thereby cause said tensioning roller to tension the strip, separate strain gauge means mounted on the separate portions of the sleeve member between the supporting arms and the point at which the sleeve member is secured to the shaft to be responsive to the torques applied to said separate portions of the sleeve member, and indicating means individually responsive to said separate strain gauge means for separately indicating the tensions on the two edge portions of the strip.

6. In a strip tensioning device, a tensioning roller disposed to be made to bear against a strip of material extending between adjacent work devices and thereby subject the strip to tension, a supporting arm for each end of said roller,

v means rotatably mounting each end of the roller on its supporting arm, a rotatably mounted shaft, a sleeve member mounted concentric with and overlying a portion of said shaft at one end thereof, means attached to the adjacent ends of said shaft and said sleeve member for applying a torque thereto, means securing said supporting arms to the other ends of said shaft and said sleeve member, respectivetly, separate strain gauge means mounted on said sleeve intermedi ate its ends and on said shaft intermediate said supporting arms to be responsive to the strain of said sleeve and to the-strain of said shaft, respectively, and separate indicating means individuallyresponsive to said separate strain gauge means for separately indicating the tensions on the two side edge portions of the strip.

GERHARD P. LESSMANN. 

